Problems with the starter, the electrics and the general module in an e34 from 4/1995

Hello there,

Thank you for accepting me into this forum. First I'd like to apologize for the rather lengthy post and for possible mistakes in my language.
I'm from Germany and I own an E34 518i sedan from 4/1995 that I indeed love very much. But recently the car has been troubling me. I'm having serious electric failures.

The problems are as following: No crank when turning the key, no power windows, no sunroof, no central locking, no radio, no interior lights, no wipers at all (not even the highest setting).
The car starts when you push it downhill and when you bypass the starter in the big wiring loom right below the windshield.

However, none of the solutions that were offered in this thread (and all others on the internet) have worked for me. I'll now give a short recap of what I found and what I tried:

All fuses in the engine bay are ok. The fusible link next to the battery in the engine bay appears to have no hairline cracks. I found that my carpet on the left hand side of the car was very, very wet. Water was also beneath the left rear seat where the rear-power-distribution-box sits. This must be somehow related to my problems.
I checked all fuses at this location and they are also ok.
I removed the seats and the carpet to dry them. I then followed the instructions from the thread that I found on this forum and opened the wiring loom that sits beneath the rear carpet on the left side close to the rear seat. There were many corroded connections which I soldered back together. This brought the interior lights and the radio back to life. All other systems stayed dead. I removed the relay-module and the general-module and the three relays from the rear-power-distribution-box and dried them over night with dry beads. No effect.
I then concluded that my failures must stem from a broken general module. I bought a used GM and a used RM from ebay with the correct part numbers. (GM = 61358368571 / RM = 31351379741).
Today I tried to install them which brought no change at all.
I then removed the GM out of curiousity and suddenly the engine fired right up when turning the key. Naturally, all other systems didn't work.

I feel like I'm in a dead end now. Why does the engine suddenly start properly without the GM? Is it possible that the GM interferes with my anti-theft-module? (I should have the EWS II). I tried finding the EWSII but had no success. Is there maybe a way to bypass it? (Not trying to steal a car or do anything illegal).
Does anyone have an idea which other wires I should check?

A bing thank you in advance to everyone who has an Idea how to help me.

thanks for your reply. I honestly don't know if my car even has a DWA since it has a very basic extra equipment (Executive Ausstattung). I did, however, find the little blue crash sensor (German = Stoßschalter) which was hidden quite well under the left rear seat. Is there any way to check if that crash sensor is still working properly? It rattles when you shake it - but I guess that's how it is supposed to be.

A few days ago I found the leak where the water was getting inside the war. There were two quite large rustholes (both ca. 5 cm2 in size) in the drivers footwell, right beneath the location where the loudspeaker is mounted. Thanks to my dad's remarkable welding-skills, these holes were fixed quickly.
After I sealed the welding properly, I'll finally be able to assemble most of the interior back together so that I can drive the car again.

I was also thinking about the wiring loom that leats to the trunk hatch. I read that these wires break quite frequently and since I've had problems with the central locking at the trunk-lock for ages, maybe that's the culprit.
Maybe the GM somehow notices that there's a short in the trunk-wiring-loom and registers this as a possible break-in-attempt, so it sends this information to the EWS which blocks the starter? That's why the car starts fine without the GM...?

As far as I know the Stossschalter rattles a bit, that is normal. I have a spare one, that also rattles
There must be a reason that there are rust holes. Do you have a sunroof? If so, thru both A-pillars go the water drain hoses and end under the door, you can even pull it out behind the speakers in footwell. In case the drains are clogged, water rises there and rust starts , see here pictures https://forum.e34.de/thread.php?thre...uf+schiebedach
how to make new drain holes https://forum.e34.de/thread.php?thre...iebedachablauf
Under the doors all the wires go from rear to front/front to rear.
Trunk hatch wire loom in most cases breaks on the Touring, but also on sedans, you can also check that , some threads with faults caused by thishttps://forum.e34.de/thread.php?thre...appenkabelbaumhttps://forum.e34.de/thread.php?thre...appenkabelbaum
I would suggest you register on the German E34 forum and post there in which part of Germany you live and if there is someone near by with a diagnostic software which can diagnoze you car and then you know what is wrong and can repair based on that info.
For example in case you live in Memmingen oder München, contact Markus525itouring

Trunk loom wiring failures are quite common. I had quite a few with shredded insulation causing odd problems that you wouldn't think possible. Definitely worth a check. Hopefully all your issues will go away.

thank you for your replies which I appreciate very much.
Yesterday I checked my trunk-wiring-loom. Though there were some cables with a broken insulation, the wires themselves were intact on all cables. The cracks in the insulation are so tiny that I don't believe that a short would be possible. I'll still insulate all of them properly, though.
For now I have reassembled my car's interior and kept the GM uninstalled. This way I can drive the car, though very limited.
Honestly, I could live without the power windows and the central locking. The thing that gives me headaches is the windshield wipers. There's no way to use the car without them since Germany is a very rainy country.

My dad proposed that we bypass the motor of the wipers and install a switch on the inside of the car. Does anyone have experiences with laying cables from the engine bay to the interior?

My next guess would be the doors. Maybe there's a short in one of the door-wiring-looms.

I also bought a used crash sensor (Stoßschalter) and will replace it as soona s it has arrived.

Often the wire loom from A-pillar to door breaks And usually the driver's door. That causes a lot of problems, as these are connected with the GM.
Here is the eba for electric windows, there you can see how to unlock the plug between door and A-pillar https://bmweba.com/eba-01-29-9-786-757/amp/

thank you for these detailed information.
In order to test if the door-wiring-looms are causing the problems, I thought the following: I will disconnect the wiring looms to the drivers door, reinstall my GM and test out the functions.
This way the (maybe) broken wiring loom would be out of order and no longer be able to cause problems, right?
Or am I imagining that the things are too easy?
Otherwise I'd surely have to remove some of the interior again to access the wiring loom inside the A-pillar, which would be a shame, since I just reassembled everything a few days ago.

Maybe that will not work (not sure) as the GM is always checking and wants feedback from microswitches etc.
The problem of broken wires can be between A-pillar and door, but also inside the door, example here , click on the pics Kabelbruch Tuer http://bmwe32.pagaduan.org/
The easiest and fastest would be if you find someone with a diagnosis software for these old models. On the German forums for E34 they usually recommend to buy the diagnosis tool from https://doitauto.de/
They also have a FAQ and forum, maybe you ask there what you need https://forum.doitauto.de/

Or find someone near your home with such a software, as I recommended before.

My dad and me bypassed the wipers today - they're now powered over the cigarette-lighter. Kinda feels like a Frankenstein-BMW
Tomorrow I will get my car diagnosed with a (hopefully) proper software-tool. I'll also replace the crash-sensor.
BTW, today I also replaced the 80a fusible link in the engine bay just to be 100% sure. Unfortunately, it had no effect.